In-wheel motor system

Abstract

Disclosed is an in-wheel motor system including: an in-wheel motor mounted inside a wheel and generating a driving force; an oil pump provided adjacent to the in-wheel motor and supplying cooling oil into the in-wheel motor; and an oil tank provided under the in-wheel motor and collecting cooling oil discharged from the in-wheel motor, wherein the oil pump and the oil tank are arranged at a lower end of the in-wheel motor and between the in-wheel motor and a steering tie-rod in a longitudinal direction of a vehicle so as to be located at a more inner position than a knuckle in a widthwise direction of the vehicle. In the in-wheel motor system, the oil tank and the oil pump may be efficiently arranged to minimize the size of the oil tank and to improve the cooling performance.

What is claimed is: 
     
       1. An in-wheel motor system for a vehicle, the system comprising:
 an in-wheel motor mounted inside a wheel and configured to generate a driving force for the wheel; 
 an oil pump configured to supply cooling oil into the in-wheel motor; and 
 an oil tank configured to collect cooling oil discharged from the in-wheel motor, 
 wherein the oil pump and the oil tank are arranged at or under the lowest point of the in-wheel motor, between the in-wheel motor and a steering tie-rod, and further at a more inner position than a knuckle in a widthwise direction of the vehicle. 
 
     
     
       2. The in-wheel motor system of  claim 1 , wherein the oil pump is operated regardless of the speed and rotation direction of the wheel. 
     
     
       3. The in-wheel motor system of  claim 2 , further comprising:
 a controller configured to receive temperature information of the in-wheel motor and to control the operation of the oil pump based on the received temperature information. 
 
     
     
       4. The in-wheel motor system of  claim 1 , wherein the oil tank comprises a cooling fin protruding from an outer surface thereof. 
     
     
       5. The in-wheel motor system of  claim 1 , wherein the top of the oil tank is set at a lower level than the lowest point of the rotor of the in-wheel motor. 
     
     
       6. The in-wheel motor system of  claim 1 , wherein the in-wheel motor comprises a shaft with a hollow portion formed therein and configured to allow cooling oil to flow therethrough. 
     
     
       7. The in-wheel motor system of  claim 6 , further comprising:
 an oil hose connected to the hollow portion of the motor shaft from the oil pump so as to transfer the cooling oil to the motor shaft. 
 
     
     
       8. The in-wheel motor system of  claim 1 , further comprising:
 a decelerator connected to the in-wheel motor and configured to increase torque of the in-wheel motor, 
 wherein the oil supplied to the in-wheel motor by the oil pump is also supplied to the decelerator through an internal flow path of the in-wheel motor. 
 
     
     
       9. The in-wheel motor system of  claim 1 , wherein the cooling oil is circulated along an oil flow path formed through a shaft of the in-wheel motor, a decelerator and the knuckle. 
     
     
       10. The in-wheel motor system of  claim 1 , wherein the oil tank is connected to the knuckle at the bottom of the knuckle. 
     
     
       11. The in-wheel motor system of  claim 1 , wherein the oil tank is integrated with the knuckle. 
     
     
       12. A vehicle comprising an in-wheel motor system of  claim 1 .